Conventionally, a gross biological sample is collected from a mammal and placed in a fixative solution (such as formaldehyde). It is then transported to a laboratory where suitable pieces of the gross sample are retrieved from the solution, sectioned, mounted onto a slide, and finally stained. See e.g., U.S. Pat. Nos. 4,911,915; 5,143,714; 5,137,710; and RE 29,073.
The coloring visualization procedure that is described here is used with biological samples like biopsy tissues, fecal samples containing parasites and discrete organs and tissues like lymph nodes. It is very different from the staining procedures used on sections of tissues as for example those attached to glass slides. In this latter situation, a wide variety of stains may be used to visualize internal cellular structures and components. These latter stains also are used after sectioning.
There also are a group of colorants known under many names including the name "Marker Dyes". These materials are employed to "outline" the outer margins of tissues in a permanent fashion. This group of colorants is distinguished from the subject matter of this invention in at least three important ways.
1. Marker Dyes often are insoluble, permanent, colored materials (or become insoluble and permanent after treatment), and they usually are "painted" onto the tissues. PA1 2. Marker Dyes usually are applied either to fresh tissues, or to tissues after fixation, but before sectioning. PA1 3. The Marker Dye procedure is intended to be permanent so that the margins of the tissues (the painted areas) can be seen easily in the final slide preparation (after sectioning and after staining).